Do you believe the victim and her lawyer, or do you believe the accused abusers? That's up to you.
That's a false dichotomy. Let me draw out a possible scenario.
A girl who is trying to become an elite dancer becomes trapped by predators who both use her, and peddle her for cash or favors (or blackmail opportunities?). In the course of that, she meets a billionaire who becomes besotted with her, and she tries to use that relationship to obtain independence from her abusers through a dubious financial arrangement. The girl, now a young woman, needs that independence, and is (understandably) insecure about her future. Her abusers are vengefully using their power over her to make sure that the cost of her independence is high. Of course the young woman wants to discount their story.
The scenario, as I imagine it, is agnostic about whether the girl/young woman had a physical relationship with Katz. It can both be true (seems likely to me) that Katz is a giant creep, and that he represented a major positive change in the girl/woman's life *from her point of view*.
I feel absolutely certain of is that the Buttons are absolutely horrible abusers. The fact that they had her texts ready for production is, for me, pretty blatant evidence of their scheming. Their admissions that they had a sexual relationship with a 18 year old who was totally dependent upon them for her career is already terribly awful, and the reality seems very likely much worse that that.
I feel less certain about Katz's behavior because I don't understand the full context of the texts. It seems creepy, and that coheres with other reports of Katz's creepiness. I don't see how we get a complete picture unless there's a defamation suit, and I don't understand how that works in Canada. I tend to understand that in the US, Katz may have more to lose than to gain from that.
This is why I want to know how Katz got connected to the victim in the first place. If it was through the Buttons, that's really bad, and I don't really need to know much more to judge him.
In my almost 50 years
as a guy, I've found that it's really easy to spot creepy behavior, and dissociate oneself from it. Creeps say creepy stuff as trial balloons to see if you'll go along with it. If you raise your eyebrows, and find any excuse to walk away, they know not to bother you again. If Katz associates with awful creeps like the Buttons, he's a creep.